Properties

Label 20.4.e.a
Level $20$
Weight $4$
Character orbit 20.e
Analytic conductor $1.180$
Analytic rank $0$
Dimension $2$
CM discriminant -4
Inner twists $4$

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Newspace parameters

Copy content comment:Compute space of new eigenforms
 
Copy content gp:[N,k,chi] = [20,4,Mod(3,20)] mf = mfinit([N,k,chi],0) lf = mfeigenbasis(mf)
 
Copy content sage:from sage.modular.dirichlet import DirichletCharacter H = DirichletGroup(20, base_ring=CyclotomicField(4)) chi = DirichletCharacter(H, H._module([2, 3])) N = Newforms(chi, 4, names="a")
 
Copy content magma://Please install CHIMP (https://github.com/edgarcosta/CHIMP) if you want to run this code chi := DirichletCharacter("20.3"); S:= CuspForms(chi, 4); N := Newforms(S);
 
Level: \( N \) \(=\) \( 20 = 2^{2} \cdot 5 \)
Weight: \( k \) \(=\) \( 4 \)
Character orbit: \([\chi]\) \(=\) 20.e (of order \(4\), degree \(2\), minimal)

Newform invariants

Copy content comment:select newform
 
Copy content sage:traces = [2] f = next(g for g in N if [g.coefficient(i+1).trace() for i in range(1)] == traces)
 
Copy content gp:f = lf[1] \\ Warning: the index may be different
 
Self dual: no
Analytic conductor: \(1.18003820011\)
Analytic rank: \(0\)
Dimension: \(2\)
Coefficient field: \(\Q(\sqrt{-1}) \)
Copy content comment:defining polynomial
 
Copy content gp:f.mod \\ as an extension of the character field
 
Defining polynomial: \( x^{2} + 1 \) Copy content Toggle raw display
Coefficient ring: \(\Z[a_1, \ldots, a_{5}]\)
Coefficient ring index: \( 1 \)
Twist minimal: yes
Sato-Tate group: $\mathrm{U}(1)[D_{4}]$

$q$-expansion

Copy content comment:q-expansion
 
Copy content sage:f.q_expansion() # note that sage often uses an isomorphic number field
 
Copy content gp:mfcoefs(f, 20)
 

Coefficients of the \(q\)-expansion are expressed in terms of \(i = \sqrt{-1}\). We also show the integral \(q\)-expansion of the trace form.

\(f(q)\) \(=\) \( q + (2 i + 2) q^{2} + 8 i q^{4} + ( - 11 i - 2) q^{5} + (16 i - 16) q^{8} - 27 i q^{9} + ( - 26 i + 18) q^{10} + (37 i - 37) q^{13} - 64 q^{16} + (99 i + 99) q^{17} + ( - 54 i + 54) q^{18} + ( - 16 i + 88) q^{20} + \cdots + (686 i - 686) q^{98} +O(q^{100}) \) Copy content Toggle raw display
\(\operatorname{Tr}(f)(q)\) \(=\) \( 2 q + 4 q^{2} - 4 q^{5} - 32 q^{8} + 36 q^{10} - 74 q^{13} - 128 q^{16} + 198 q^{17} + 108 q^{18} + 176 q^{20} - 234 q^{25} - 296 q^{26} - 256 q^{32} + 432 q^{36} - 182 q^{37} + 416 q^{40} + 944 q^{41}+ \cdots - 1372 q^{98}+O(q^{100}) \) Copy content Toggle raw display

Character values

We give the values of \(\chi\) on generators for \(\left(\mathbb{Z}/20\mathbb{Z}\right)^\times\).

\(n\) \(11\) \(17\)
\(\chi(n)\) \(-1\) \(i\)

Embeddings

For each embedding \(\iota_m\) of the coefficient field, the values \(\iota_m(a_n)\) are shown below.

For more information on an embedded modular form you can click on its label.

Copy content comment:embeddings in the coefficient field
 
Copy content gp:mfembed(f)
 
Label   \(\iota_m(\nu)\) \( a_{2} \) \( a_{3} \) \( a_{4} \) \( a_{5} \) \( a_{6} \) \( a_{7} \) \( a_{8} \) \( a_{9} \) \( a_{10} \)
3.1
1.00000i
1.00000i
2.00000 2.00000i 0 8.00000i −2.00000 + 11.0000i 0 0 −16.0000 16.0000i 27.0000i 18.0000 + 26.0000i
7.1 2.00000 + 2.00000i 0 8.00000i −2.00000 11.0000i 0 0 −16.0000 + 16.0000i 27.0000i 18.0000 26.0000i
\(n\): e.g. 2-40 or 990-1000
Significant digits:
Format:

Inner twists

Char Parity Ord Mult Type
1.a even 1 1 trivial
4.b odd 2 1 CM by \(\Q(\sqrt{-1}) \)
5.c odd 4 1 inner
20.e even 4 1 inner

Twists

       By twisting character orbit
Char Parity Ord Mult Type Twist Min Dim
1.a even 1 1 trivial 20.4.e.a 2
3.b odd 2 1 180.4.k.a 2
4.b odd 2 1 CM 20.4.e.a 2
5.b even 2 1 100.4.e.a 2
5.c odd 4 1 inner 20.4.e.a 2
5.c odd 4 1 100.4.e.a 2
8.b even 2 1 320.4.n.c 2
8.d odd 2 1 320.4.n.c 2
12.b even 2 1 180.4.k.a 2
15.e even 4 1 180.4.k.a 2
20.d odd 2 1 100.4.e.a 2
20.e even 4 1 inner 20.4.e.a 2
20.e even 4 1 100.4.e.a 2
40.i odd 4 1 320.4.n.c 2
40.k even 4 1 320.4.n.c 2
60.l odd 4 1 180.4.k.a 2
    
        By twisted newform orbit
Twist Min Dim Char Parity Ord Mult Type
20.4.e.a 2 1.a even 1 1 trivial
20.4.e.a 2 4.b odd 2 1 CM
20.4.e.a 2 5.c odd 4 1 inner
20.4.e.a 2 20.e even 4 1 inner
100.4.e.a 2 5.b even 2 1
100.4.e.a 2 5.c odd 4 1
100.4.e.a 2 20.d odd 2 1
100.4.e.a 2 20.e even 4 1
180.4.k.a 2 3.b odd 2 1
180.4.k.a 2 12.b even 2 1
180.4.k.a 2 15.e even 4 1
180.4.k.a 2 60.l odd 4 1
320.4.n.c 2 8.b even 2 1
320.4.n.c 2 8.d odd 2 1
320.4.n.c 2 40.i odd 4 1
320.4.n.c 2 40.k even 4 1

Hecke kernels

This newform subspace can be constructed as the kernel of the linear operator \( T_{3} \) acting on \(S_{4}^{\mathrm{new}}(20, [\chi])\). Copy content Toggle raw display

Hecke characteristic polynomials

$p$ $F_p(T)$
$2$ \( T^{2} - 4T + 8 \) Copy content Toggle raw display
$3$ \( T^{2} \) Copy content Toggle raw display
$5$ \( T^{2} + 4T + 125 \) Copy content Toggle raw display
$7$ \( T^{2} \) Copy content Toggle raw display
$11$ \( T^{2} \) Copy content Toggle raw display
$13$ \( T^{2} + 74T + 2738 \) Copy content Toggle raw display
$17$ \( T^{2} - 198T + 19602 \) Copy content Toggle raw display
$19$ \( T^{2} \) Copy content Toggle raw display
$23$ \( T^{2} \) Copy content Toggle raw display
$29$ \( T^{2} + 80656 \) Copy content Toggle raw display
$31$ \( T^{2} \) Copy content Toggle raw display
$37$ \( T^{2} + 182T + 16562 \) Copy content Toggle raw display
$41$ \( (T - 472)^{2} \) Copy content Toggle raw display
$43$ \( T^{2} \) Copy content Toggle raw display
$47$ \( T^{2} \) Copy content Toggle raw display
$53$ \( T^{2} + 54T + 1458 \) Copy content Toggle raw display
$59$ \( T^{2} \) Copy content Toggle raw display
$61$ \( (T + 468)^{2} \) Copy content Toggle raw display
$67$ \( T^{2} \) Copy content Toggle raw display
$71$ \( T^{2} \) Copy content Toggle raw display
$73$ \( T^{2} - 506T + 128018 \) Copy content Toggle raw display
$79$ \( T^{2} \) Copy content Toggle raw display
$83$ \( T^{2} \) Copy content Toggle raw display
$89$ \( T^{2} + 30976 \) Copy content Toggle raw display
$97$ \( T^{2} + 1222 T + 746642 \) Copy content Toggle raw display
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